chore: add comment about crossorigin attribute for script module

[sapphi-red]

Description

I didn't know about the reason why crossorigin attribute is set for <script type="module">. Digging around the crossorigin attribute and <link rel="preload">, I guess this is the reason.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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